Which is correct pushing elbows out to the sides or behind you? or does it just work different areas such as arms or chest?

erm.. put ur hands under your shoulders. then just push without twisting the hands. thats how ur motion should be. natural. unless u need help pushing, then it might help if u stick ur elbows out more.

Your elbows should be at about a 45 degree angle, so fairly close to your body, not flared. Typically when people flare their elbows, they lack the strength to do them with good form. If you continue doing your pushups with flared elbows, there is a much higher risk you will develop shoulder problems in the future as this puts a lot of pressure on the delicate rotator cuff muscles. Also remember to go all the way down, feeling a contraction in your shoulder blades, and coming all the way up, rising your scapular up slightly. Perfect form EVERY REP! ;-)

Ok thanks,by flaring do you mean outwards, i.e perpendicular to my body? When I do push ups I keep my elbows touching my sides nearly,straight backwards

If your elbows are touching your sides, you're doing more of a CLOSE grip push-up, which hits your triceps a little more. It might help you to look up some push-up demonstrations on you-tube... Most important, don't allow your arms to make 90 degree angles to your body. This is very tough on your shoulders!

This is especially important when doing wide grip push ups, since the torque is a little more extreme... Just something to keep in mind!

then does it apply for the wide rows too? its the same, only pulling...

Thanks for the info anyway

Yes, you could apply this to wide-grip rows as well... Barbell rows in general are considered unhealthy for your shoulder due to the rotation that occurs during the movement, possibly leading to an impingement issue. I still think that the row is an excellent exercise, but it's especially important to be careful with the amount of weight you're using and how often you're performing this particular exercise...